1. Field of the Invention
The present invention generally relates to a remote monitoring unit, and more particularly to a remote monitoring unit for monitoring the security of a remote site building from a central control equipment via radio transmission.
2. Description of the Prior Art
Conventionally, a security control system has been utilized as a counter measure, for preventing crimes and disasters in a building (or an office) whose security is to be monitored. The security control system generally includes a camera, a fire detecting sensor and other sensors installed at a remote site location to be monitored, and a central control equipment installed in a security corporation. A video signal output by the camera and detection signals output by the sensors are transmitted from the building to the central control equipment via a transmission cable linking the monitored building to the central control equipment.
In a case of the security control system of the type described above, a security personnel at a location of the central control equipment always monitors the security of a plurality of buildings by means of video signals and detection signals received from the remote site, and controls operations of cameras and sensors installed in :he monitored buildings in a concentrated manner. It is known that a camera, a temperature sensor, a gas sensor and other sensors are used as surveillance sensor, installed in the monitored buildings. The temperature sensor senses the occurrence of a fire at a monitored :location by detecting a temperature change there higher than a prescribed level. The gas sensor senses the presence of smoke at the monitored location by Detecting a concentration of a specific gas there greater than a prescribed level.
When the above described monitoring system is used for security purposes, it is necessary to separately install several surveillance sensors such as a camera and a temperature sensor at different locations of a remote site to be monitored. Also, it is necessary to separately install several telephone lines or cables for transmitting output signals of the respective surveillance sensors from the remote site building to the central control location. Separately made installations of the sensors and the transmission lines have been very troublesome. Thus, the installation of the security control system becomes expensive, as the system requires several surveillance sensors to be placed in the remote site building.
When a showroom of the building is monitored, several surveillance sensors of the above described security control system must be placed at locations of the showroom; this is detrimental to the appearance of objects being displayed in the showroom. It is thus desirable that the surveillance sensors of the security control system are built so as to be compact and not detrimental to the appearance of the objects at the monitored locations.